1. Field of the Invention
The present invention relates to an ink-jet printer that ejects droplets of ink onto a recording medium, and a method of controlling an ink-jet printer.
2. Discussion of Related Art
There is known an ink-jet printer including an ink-jet recording head that ejects droplets of ink; an ink tank that stores an ink to be supplied to the recording head via a flexible ink-supply tube; and an air tank that stores air to be supplied to the ink tank. An example of this ink-jet printer is disclosed by Japanese Patent Application Publication No. 2004-58348 or its corresponding U.S. Patent Application Publication No. 2004/0196326A1. This ink-jet printer has such a problem that air enters the flexible ink-supply tube through its wall and, as time elapses, air bubbles grow and increase in the ink-supply tube and eventually lower an ink-ejecting performance of the ink-jet recording head. To solve this problem, the ink-jet printer periodically carries out an air discharging operation in which air is quickly supplied from the air tank to the ink tank so as to discharge forcibly the air bubbles, together with an amount of the ink, from the ink-supply tube into an outside space.